The effect of enzymatic modification and genetic background on wheat gliadin immunological properties

The immune response to gliadins extracted from 35 wheat cultivars, strains and species was investigated. With the use of a non-competitive ELISA method, we sought to examine if immune reaction occurs between wheat proteins and sera from patients sensitive to gluten, as well as between wheat proteins and rabbit antibodies against pentapeptide QQQPP. Results showed considerable differences among cultivars. Breeding strains STH 183, STH 650, STH 2804, Triticum aethiopicum and Triticum durum showed the lowest immunoreactivity of the native samples. Seventeen of selected wheat flour samples were subjected to enzymatic modifications by subtilisin and transglutaminase. Samples modified by subtilisin exhibited the most extensive change in the level of immunoreactivity of gliadin proteins. The lowest immunoreactivity was reported for the breeding strains STH 1596, STH 2804 and cultivars Tonacja and Zyta. One wheat cultivar (Tonacja), known for its high native gliadin immunoreactivity, was shown to be very susceptible to enzymatic digestion, which resulted in a reduction of its initial immunoreactivity level to low values. Immunoreactivity analysis was also conducted on extracted gliadin fractions from winter wheat strain Ostka strzelecka. The highest level of immunoreactivity to both types of antibodies we used was indicated for ω5-gliadins. It was, however, abrogated in the aftermath of enzymatic modifications.